ok, well if you don't want to do the math, you can go to a certain person in each game to see what type it is:

The type of Hidden Power can be checked in Veilstone Game Corner's prize house in Pokémon Platinum, the Celadon Game Corner in Pokémon HeartGold and SoulSilver, and in Mistralton City's Pokémon Center in Pokémon Black and White. There remains no in-game way to determine the power level directly, however.